content: /**
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
   * compliance with the License. You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software distributed under the License is
   * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
   * the License for the specific language governing permissions and limitations under the License.
   */
  package io.reactivex.observable.internal.operators;
  
  import java.util.Arrays;
  import java.util.concurrent.atomic.*;
  
  import io.reactivex.common.*;
  import io.reactivex.common.annotations.*;
  import io.reactivex.common.exceptions.Exceptions;
  import io.reactivex.common.functions.Function;
  import io.reactivex.common.internal.disposables.DisposableHelper;
  import io.reactivex.common.internal.functions.ObjectHelper;
  import io.reactivex.common.internal.utils.AtomicThrowable;
  import io.reactivex.observable.*;
  import io.reactivex.observable.internal.disposables.EmptyDisposable;
  import io.reactivex.observable.internal.utils.HalfSerializer;
  
  /**
   * Combines a main sequence of values with the latest from multiple other sequences via
   * a selector function.
   *
   * @param <T> the main sequence's type
   * @param <R> the output type
   */
  public final class ObservableWithLatestFromMany<T, R> extends AbstractObservableWithUpstream<T, R> {
  
      @Nullable
      final ObservableSource<?>[] otherArray;
  
      @Nullable
      final Iterable<? extends ObservableSource<?>> otherIterable;
  
      @NonNull
      final Function<? super Object[], R> combiner;
  
      public ObservableWithLatestFromMany(@NonNull ObservableSource<T> source, @NonNull ObservableSource<?>[] otherArray, @NonNull Function<? super Object[], R> combiner) {
          super(source);
          this.otherArray = otherArray;
          this.otherIterable = null;
          this.combiner = combiner;
      }
  
      public ObservableWithLatestFromMany(@NonNull ObservableSource<T> source, @NonNull Iterable<? extends ObservableSource<?>> otherIterable, @NonNull Function<? super Object[], R> combiner) {
          super(source);
          this.otherArray = null;
          this.otherIterable = otherIterable;
          this.combiner = combiner;
      }
  
      @Override
      protected void subscribeActual(Observer<? super R> s) {
          ObservableSource<?>[] others = otherArray;
          int n = 0;
          if (others == null) {
              others = new ObservableSource[8];
  
              try {
                  for (ObservableSource<?> p : otherIterable) {
                      if (n == others.length) {
                          others = Arrays.copyOf(others, n + (n >> 1));
                      }
                      others[n++] = p;
                  }
              } catch (Throwable ex) {
                  Exceptions.throwIfFatal(ex);
                  EmptyDisposable.error(ex, s);
                  return;
              }
  
          } else {
              n = others.length;
          }
  
          if (n == 0) {
              new ObservableMap<T, R>(source, new SingletonArrayFunc()).subscribeActual(s);
              return;
          }
  
          WithLatestFromObserver<T, R> parent = new WithLatestFromObserver<T, R>(s, combiner, n);
          s.onSubscribe(parent);
          parent.subscribe(others, n);
  
          source.subscribe(parent);
      }
  
      static final class WithLatestFromObserver<T, R>
      extends AtomicInteger
      implements Observer<T>, Disposable {
  
          private static final long serialVersionUID = 1577321883966341961L;
  
          final Observer<? super R> actual;
  
          final Function<? super Object[], R> combiner;
  
          final WithLatestInnerObserver[] observers;
  
          final AtomicReferenceArray<Object> values;
  
          final AtomicReference<Disposable> d;
  
          final AtomicThrowable error;
  
          volatile boolean done;
  
          WithLatestFromObserver(Observer<? super R> actual, Function<? super Object[], R> combiner, int n) {
              this.actual = actual;
              this.combiner = combiner;
              WithLatestInnerObserver[] s = new WithLatestInnerObserver[n];
              for (int i = 0; i < n; i++) {
                  s[i] = new WithLatestInnerObserver(this, i);
              }
              this.observers = s;
              this.values = new AtomicReferenceArray<Object>(n);
              this.d = new AtomicReference<Disposable>();
              this.error = new AtomicThrowable();
          }
  
          void subscribe(ObservableSource<?>[] others, int n) {
              WithLatestInnerObserver[] observers = this.observers;
              AtomicReference<Disposable> s = this.d;
              for (int i = 0; i < n; i++) {
                  if (DisposableHelper.isDisposed(s.get()) || done) {
                      return;
                  }
                  others[i].subscribe(observers[i]);
              }
          }
  
          @Override
          public void onSubscribe(Disposable d) {
              DisposableHelper.setOnce(this.d, d);
          }
  
          @Override
          public void onNext(T t) {
              if (done) {
                  return;
              }
              AtomicReferenceArray<Object> ara = values;
              int n = ara.length();
              Object[] objects = new Object[n + 1];
              objects[0] = t;
  
              for (int i = 0; i < n; i++) {
                  Object o = ara.get(i);
                  if (o == null) {
                      // no latest, skip this value
                      return;
                  }
                  objects[i + 1] = o;
              }
  
              R v;
  
              try {
                  v = ObjectHelper.requireNonNull(combiner.apply(objects), "combiner returned a null value");
              } catch (Throwable ex) {
                  Exceptions.throwIfFatal(ex);
                  dispose();
                  onError(ex);
                  return;
              }
  
              HalfSerializer.onNext(actual, v, this, error);
          }
  
          @Override
          public void onError(Throwable t) {
              if (done) {
                  RxJavaCommonPlugins.onError(t);
                  return;
              }
              done = true;
              cancelAllBut(-1);
              HalfSerializer.onError(actual, t, this, error);
          }
  
          @Override
          public void onComplete() {
              if (!done) {
                  done = true;
                  cancelAllBut(-1);
                  HalfSerializer.onComplete(actual, this, error);
              }
          }
  
          @Override
          public boolean isDisposed() {
              return DisposableHelper.isDisposed(d.get());
          }
  
          @Override
          public void dispose() {
              DisposableHelper.dispose(d);
              for (WithLatestInnerObserver s : observers) {
                  s.dispose();
              }
          }
  
          void innerNext(int index, Object o) {
              values.set(index, o);
          }
  
          void innerError(int index, Throwable t) {
              done = true;
              DisposableHelper.dispose(d);
              cancelAllBut(index);
              HalfSerializer.onError(actual, t, this, error);
          }
  
          void innerComplete(int index, boolean nonEmpty) {
              if (!nonEmpty) {
                  done = true;
                  cancelAllBut(index);
                  HalfSerializer.onComplete(actual, this, error);
              }
          }
  
          void cancelAllBut(int index) {
              WithLatestInnerObserver[] observers = this.observers;
              for (int i = 0; i < observers.length; i++) {
                  if (i != index) {
                      observers[i].dispose();
                  }
              }
          }
      }
  
      static final class WithLatestInnerObserver
      extends AtomicReference<Disposable>
      implements Observer<Object> {
  
          private static final long serialVersionUID = 3256684027868224024L;
  
          final WithLatestFromObserver<?, ?> parent;
  
          final int index;
  
          boolean hasValue;
  
          WithLatestInnerObserver(WithLatestFromObserver<?, ?> parent, int index) {
              this.parent = parent;
              this.index = index;
          }
  
          @Override
          public void onSubscribe(Disposable d) {
              DisposableHelper.setOnce(this, d);
          }
  
          @Override
          public void onNext(Object t) {
              if (!hasValue) {
                  hasValue = true;
              }
              parent.innerNext(index, t);
          }
  
          @Override
          public void onError(Throwable t) {
              parent.innerError(index, t);
          }
  
          @Override
          public void onComplete() {
              parent.innerComplete(index, hasValue);
          }
  
          public void dispose() {
              DisposableHelper.dispose(this);
          }
      }
  
      final class SingletonArrayFunc implements Function<T, R> {
          @Override
          public R apply(T t) throws Exception {
              return ObjectHelper.requireNonNull(combiner.apply(new Object[] { t }), "The combiner returned a null value");
          }
      }
  }
  